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Medicine interactions

MAOI antidepressants: food, tyramine and medicine interactions

Monoamine oxidase inhibitors (MAOIs) are now rarely used for depression, but they carry some of the most important food and medicine warnings in prescribing. Certain foods, other antidepressants and strong painkillers can trigger a dangerous reaction. This guide explains the pattern and why the restrictions last after the last dose.

Last checked: 2026-10-03

Key facts

At a glance.

  • Rare but important

    The NHS says MAOIs are now rarely used to treat depression, so many prescribers and patients meet them seldom.

  • Foods flagged

    MedlinePlus says to avoid high-tyramine foods including smoked, aged, improperly stored or spoiled meat, poultry, fish or cheese, certain fruits, vegetables and beans, alcoholic drinks and fermented yeast products.

  • Caffeine

    MedlinePlus also advises avoiding foods and drinks containing caffeine during phenelzine treatment.

  • Long tail

    MedlinePlus says phenelzine may remain in the body for several weeks after stopping, so new medicines should be checked during that time.

  • Medicine clashes

    NHS pages for tramadol, sertraline and venlafaxine say not to combine them with MAOIs.

What MAOIs do

These medicines block monoamine oxidase, an enzyme that breaks down chemical messengers such as serotonin and noradrenaline and also breaks down tyramine from food. Blocking it can help depression that has not responded to other treatments, but it removes a safety mechanism the body normally relies on.

Examples include phenelzine and tranylcypromine for depression, moclobemide in a milder form and selegiline and rasagiline used in Parkinson's disease. The NHS tramadol page lists moclobemide, phenelzine, rasagiline and selegiline as MAOIs.

Tyramine and the food rules

Tyramine is formed as protein-rich foods age, ferment or spoil. Normally it is broken down in the gut wall. With an MAOI that breakdown is blocked, so a large amount can reach the bloodstream and trigger a sharp rise in blood pressure.

MedlinePlus describes the foods to avoid for phenelzine as meat, poultry, fish or cheese that has been smoked, aged, improperly stored or spoiled, certain fruits, vegetables and beans, alcoholic beverages and fermented yeast products, and adds caffeine. Your prescriber will give a specific list and the exact rules differ between MAOIs.

  • Smoked, aged, spoiled or improperly stored meat, poultry and fish.

  • Aged cheese.

  • Alcoholic drinks.

  • Fermented yeast products.

  • Caffeine.

The hypertensive reaction

MedlinePlus lists symptoms needing immediate medical attention: headache, a slow, fast or pounding heartbeat, neck stiffness or soreness, chest pain, nausea, vomiting, sweating, wide pupils and eyes more sensitive to light than usual.

A severe headache or chest pain on an MAOI after a meal or a new medicine is an emergency. Call 999 or go to A&E and tell them you take an MAOI; bring the packaging. Do not wait to see whether it passes.

Medicines that must not be combined

The NHS tramadol page says not to take MAOIs with tramadol because of serious side effects such as anxiety, confusion and hallucinations. The NHS sertraline and venlafaxine pages say not to take MAOIs such as moclobemide and selegiline with them, and the citalopram and morphine pages list MAOIs among the medicines that interact.

Our serotonin syndrome guide describes the risk when serotonin-raising medicines are combined. MedlinePlus also lists nonprescription or herbal products that may interact with phenelzine, including phenylalanine (DLPA), rauwolfia, tyrosine and tryptophan.

Switching and stopping

MedlinePlus says phenelzine may remain in your body for several weeks after you stop, and that in the first few weeks you should tell your doctor and pharmacist that you recently stopped before taking any new medicine. The same logic applies when switching to another antidepressant: a gap is needed and the prescriber sets it.

Do not stop an MAOI or start a replacement on your own. Sudden changes carry risks both from interactions and from the original illness returning.

Practical safety habits

Carry a list of your medicines and tell every professional you see, including dentists, who may offer a local anaesthetic, and out-of-hours doctors. Ask a pharmacist before buying any cough, cold or decongestant product, and avoid starting herbal supplements without checking.

Keep food fresh and eat it soon after it is prepared, because storage affects tyramine content. Ask your prescriber for written dietary guidance specific to your tablet.

Frequently asked

Questions people ask.

Quick, plain-English answers to the questions we hear most.

  • Which foods are risky on an MAOI?

    MedlinePlus lists smoked, aged, improperly stored or spoiled meat, poultry, fish or cheese, certain fruits, vegetables and beans, alcoholic drinks and fermented yeast products. Your prescriber will give a list for your tablet.

  • Why does tyramine matter?

    MAOIs block its normal breakdown, so it can build up and raise blood pressure sharply. The result can be a hypertensive reaction with headache and chest pain.

  • Do I still need precautions after stopping?

    Yes. MedlinePlus says phenelzine may remain in the body for several weeks, so tell prescribers and pharmacists you recently stopped before taking anything new.

  • Can I take tramadol with an MAOI?

    No. The NHS tramadol page says not to, because of serious side effects such as anxiety, confusion and hallucinations.

  • Can I take sertraline or venlafaxine with an MAOI?

    The NHS pages for both say MAOIs such as moclobemide and selegiline should not be taken with them.

  • What symptoms need an emergency response?

    Severe headache, pounding heartbeat, neck stiffness, chest pain, vomiting, sweating or sensitivity to light. Call 999 and say you take an MAOI.

  • Are MAOIs commonly prescribed in the UK?

    The NHS says they are now rarely used to treat depression. They remain an option for some people under specialist supervision.

  • Do cold remedies matter?

    Many cold products contain ingredients that raise blood pressure. We did not retrieve a specific source, so ask a pharmacist before buying any.

  • Does caffeine matter?

    MedlinePlus advises avoiding foods and drinks containing caffeine during phenelzine treatment. Ask your prescriber about your specific medicine.

Where this comes from

Sources and checking.

This guide is for information, not medical advice.

Your GP or consultant knows your history and can tell you which parts apply to you. If your symptoms are severe, rapidly worsening, or come with red-flag features, seek urgent medical care. Figures and availability change, so treat them as a guide and confirm with the provider.

Published 2026-10-03, next review 2027-10-03.

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